1. Field of the Invention:
This invention generally relates to anchoring arrangements for floating structures and, more particularly, to relatively permanent anchoring arrangements for floating structures, such as decommissioned tankers.
2. Description of the Prior Art:
There are several prior art anchoring arrangements known, which comprise any of the known types of anchoring systems. These cater only to the requirements of tankers and other floating structures which are either at a dock or a harbor. Occasionally, certain conventional anchoring arrangements are used to anchor vessels in the open sea as well. However, conventional anchoring will not be very effective if the floating structure or vessel is in high seas, especially when it is required to connect a transfer hose or an underwater pipeline to the floating vessel. Even with anchoring, a certain degree of shifting of the floating structure, or even a certain degree of rotation of the floating structure, might occur in high seas. At least one consequence of such shifting or rotation is that the transfer hose, for example, tends to get damaged or even disconnected, causing serious consequences. The problem is especially serious in the case of ocean vessels, such as decommissioned tankers, wherein there is need for having at least a transfer hose constantly connected to the tanker through the ocean water either to the sea bed or the shore or another vessel. Certain underwater structural arrangements have been used in heretofore to cater to the needs of stably and permanently anchoring decommissioned tankers, simultaneously making provision for a transfer pipe connected between the tanker and the sea bed. However, prior art arrangements have always required a significant mass of steel to fabricate the underwater structure, making the equipment expensive from the point of view of installation and maintenance. Furthermore, it has been found that it is desirable to provide an underwater anchor means which permits relative rotary movement between the tanker superstructure and the anchoring arrangement to make a provision for oscillatory and rotary swaying movements of the tanker superstructure in high seas. Preferably, the underwater means should have a massive bearing mechanism to easily permit such movement. Also, it is desirable that there should be easy access for maintenance personnel to reach the bearing mechanism and attend to maintenance and replacement work, preferably in a dry atmosphere. Such facilities are not available in any known prior art anchoring arrangement.
There is, therefore, a great need for an anchoring arrangement devoid of the disadvantages and limitations of prior art while including the more desirable features which are discussed above.